Delay circuits are used in various electronic circuits for functions such as matching timing delays inside integrated circuits to avoid race conditions, and for device independent time delays. The circuits for generating the device independent time delays are generally either hybrid delay lines which use small discrete L and C elements, or monostable multivibrator integrated circuits or "one shots".
The device independent time delay circuits are designed to be essentially insensitive to variations in ambient temperature, on the order of 1000 parts per million (PPM) per degree Centigrade and in variations of supply voltage. The term "essentially", as used herein, means closely approximating to a degree sufficient for practical purposes.
At present, because of the relative complexity of one shots, the only viable form of device independent delay circuits for providing a plurality of delayed signals from one input signal is the hybrid delay line. However, the hybrid delay lines tend to be expensive to manufacture compared to most integrated circuits, and tend not to be as reliable as monolithic I.C.'s.
It can therefore be appreciated that an independent time delay circuit which is able to provide a plurality of time delays from a single input signal and which can be fabricated using standard integrated circuit fabrication techniques is highly desirable.